Treat functions generated for closurization as equivalent to their source functions.

tests/lib/mirrors/closurization_equivalence_test.dart

+// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'dart:mirrors';
+import 'package:expect/expect.dart';
+
+topLevelMethod() {}
+class C {
+  static staticMethod() {}
+  instanceMethod() {}
+}
+
+main() {
+  LibraryMirror thisLibrary = reflectClass(C).owner;
+  Expect.equals(thisLibrary.declarations[#topLevelMethod],
+                (reflect(topLevelMethod) as ClosureMirror).function,
+                "topLevel");
+
+  Expect.equals(reflectClass(C).declarations[#staticMethod],
+                (reflect(C.staticMethod) as ClosureMirror).function,
+                "static");
+
+  Expect.equals(reflectClass(C).declarations[#instanceMethod],
+                (reflect(new C().instanceMethod) as ClosureMirror).function,
+                "instance");
+}